Electrode Carbon Fiber Conductive Path Stability

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Solution Overview

Problem

Existing secondary batteries face challenges in achieving both high input/output performance and cycle performance due to the breakage of electro-conduction paths caused by volume changes in active materials when mixed with solid electrolyte particles, which affect lithium ion conductivity and electronic conductivity.

Innovation Solution

An electrode with an active material-containing layer comprising titanium-containing composite oxide, inorganic solid particles with lithium ion conductivity, and carbon fiber, where the carbon fiber forms a stable electro-conduction path and the inorganic solid particles enhance lithium ion conductivity, maintaining the path even during volume changes of the active material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If carbon fiber is added to maintain electro-conduction path stability, then electro-conduction path stability is improved, but device complexity increases

Engineering Contradiction:

Improveelectro-conduction path stabilityVSAvoidelectrode composition complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The carbon fiber serves multiple functions simultaneously: it maintains electro-conduction path stability during active material volume changes, provides structural support within the electrode matrix, and facilitates electron transport. This multi-functionality reduces the need for additional separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention optimizes the amount and distribution parameters of carbon fiber within the electrode to achieve stable electro-conduction with minimal addition. By controlling the carbon fiber content within specific ranges and ensuring uniform distribution, the electrode achieves path stability without excessive complexity.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution results in a secondary battery with improved input/output performance and cycle performance by maintaining electro-conduction and lithium ion conductivity, while preventing the breakage of electro-conduction paths during charge and discharge cycles.

Implementation Method 1

inorganic solid particles having lithium ion conductivity

Methodology Applied

Scientific EffectLithium ion conductivity: Fast Ion Conductor

Implementation Method 2

carbon fiber forms a stable electro-conduction path

Methodology Applied

Scientific EffectElectronic conductivity: Conduction (electrical)

Data Source

PatentUS11380885B2Electrode, secondary battery, battery pack, and vehicle

Publication Date: 2022.07.05 KK TOSHIBA

AI summary

According to one embodiment, an electrode is provided. The electrode includes an active material-containing layer. The active material-containing layer includes: an active material including a titanium-containing composite oxide; inorganic solid particles having lithium ion conductivity; and carbon fiber. The active material-containing layer has a first peak indicating a maximum log differential pore volume in a log differential pore volume distribution curve according to mercury porosimetry. A pore diameter PD at the first peak is 0.01 μm to 0.1 μm. The first peak has a full width at half maximum of 0.05 μm or less.